The invention addresses a method for measuring of caster, camber, and king-pin-inclination on motor vehicles by means of inclinometers, and also measuring apparatus for accomplishing such method.
The measurement of wheel-toe, camber, caster and king-pin-inclination, especially on passenger cars, presupposes, by definition, the fact that the longitudinal axis of the vehicle is positioned parallel to a horizontal plane during the measurements. Further, the transverse axis of the vehicle must also be positioned parallel to a horizontal plane if the king-pin-inclination and camber are measured.
Only in the rarest cases are these premises given in practice, and influences may be created by the loading condition of the vehicle to be measured. In order to achieve parallel positioning of the longitudinal and transverse vehicle axes relative to a horizontal plane, various methods are used in practice. For example, the vehicle is often loaded down with additional weights until a given spring deflection is achieved. Alternatively vehicles are loaded down with fixed weights, for instance 75 kg per passenger for two or four passengers, and in some cases additional weights must also be placed in the trunk. With vehicles having independent rear suspensions considerable errors in geometric values occur if the vehicles are unsymmetrically loaded.
Some vehicle manufacturers use ropes to pull the vehicle body toward the ground and pretension the ropes so that the longitudinal and transverse axes of the vehicle assume the desired ideal position.
With all these methods additional very strict requirements are required during the measurement process especially on the positioning location with respect to the horizontal orientation thereof. With hoists, these requirements are difficult to achieve and often require exceptional efforts because of deflections as a result of the vehicle weight.